Lewis Dot Structures
Lewis structures show valence electrons and bonds.
About this topic
Lewis structures show valence electrons as dots around atomic symbols and bonds as lines. To draw one: count total valence electrons, place the least electronegative atom in the centre, join atoms with single bonds, complete octets on outer atoms, put leftover electrons on the central atom, and form double or triple bonds if needed.
Bonding pairs are shown as lines and lone pairs as dots. Formal charge, equal to valence electrons minus nonbonding electrons minus half of bonding electrons, helps pick the best structure. Hydrogen is always terminal and never central. Some molecules break the octet rule, like boron trifluoride with six electrons, or sulfur hexafluoride with twelve.
Worked example for carbon dioxide: carbon has 4 and each oxygen 6, total 16 electrons. Put carbon in the middle with single bonds to both oxygens, using 4 electrons; add 12 more as lone pairs on the oxygens; carbon has only four electrons, so move lone pairs to make two double bonds. Each atom now has eight.
Lewis structures predict shape, polarity and reactivity. Students often miscount total electrons, especially for ions, where you add electrons for negative charges and remove them for positive. Always check that your final count matches the total.
Key ideas
- Dots for valence electrons
- Lines for bonded pairs
- Satisfy the octet
Quick check
Use cases: where Lewis Dot Structures helps
- Homework: review the key idea behind Lewis Dot Structures before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Lewis Dot Structures without notes.
- Visual learning: play with the interactive lab to see how Lewis Dot Structures changes when you adjust its inputs.
- Teaching a friend: explain Lewis Dot Structures in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is Lewis Dot Structures?
Lewis structures show valence electrons and bonds.
What will I learn in Lewis Dot Structures?
Dots for valence electrons. Lines for bonded pairs. Satisfy the octet.
Is Lewis Dot Structures part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Lewis Dot Structures lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Lewis Dot Structures?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.